Rigid surfboards are manufactured from materials such as hard setting resins and closed cell rigid foam which makes it possible to produce a completely rigid surfboard with a shape that offers optimum performance. Rigid surfboards have the disadvantage of being difficult to transport and to store due to their size and the fact that they cannot be collapsed.
Inflatable surfboards have the advantage of being easy to transport and to store due to the fact that they can be deflated. However they have the disadvantage of having a poorer performance than rigid surfboards due to the fact that their method of production using flexible materials prevents them from having sufficient rigidity and a shape that offers optimum performance.
When considering surfboards, the problem of how to reconcile performance with convenience of transport and storage, has existed for years. Conventional, rigid surfboards, which can be long and very cumbersome, have emphasized this problem. This led to the introduction of inflatable stand up paddle surfboards.
However, the problem regarding the performance of inflatable surfboards is that their shape changes during use due to the weight of the user and the action of for example waves. This is due to their inherent flexibility, which also means that they cannot be produced with a suitable high performance profile, such as those found in rigid surfboards.
Various modifications to rigid surfboards have been proposed to make them easier to store and transport, including the concepts illustrated in US 20130029547 A1 and WO 2009070825 A1.
US 20130029547 A1 for example proposes cutting a conventional rigid surfboard in half and connecting the two halves when in use, so providing a surfboard that is relatively easy to transport while still retaining a relatively high level of performance.
WO 2009070825 A1 proposes cutting the surfboard into sections and hinging the sections together.
With regards to inflatable surfboards, various proposals to improve their performance have been made, including the use of stiffening plates and other devices attached to the surface of the inflatable structure as seen for example in U.S. Pat. No. 3,657,753, WO2013175160 and U.S. Pat. No. 7,662,006.
U.S. Pat. No. 3,657,753 describes a folding inflatable surfboard.
WO2013175160 proposes attaching stiffeners to the side of the inflatable surfboard.
Another question that arises in connection with inflatable surfboards is how to attach fins to their underside. Today it is usual for inflatable stand up surfboards to be equipped with fins inserted into rigid fin box supports attached to the underside surface of the end of the inflatable surfboard.
U.S. Pat. No. 7,662,006 describes an example of an inflatable surfboard in which the fin box supports are incorporated into a rigid fin box support structure that takes the form of a plate that is attached to the underneath surface of the inflatable surfboard and extends to the edge of the rear part of the inflatable surfboard. The edge of the plate is coincident with the edge of the board, so helps to give a better edge to the rail. However, the principal idea described in this patent is a system for constructing an inflatable surfboard by using moulds formed from conventional rigid surfboards to produce flexible inflatable surfboards that have a better shape than a conventional inflatable surfboard together with the advantage of being collapsible and so easy to store and to transport.